Binding element for a building wall structure

ABSTRACT

A binding element for a building wall structure, wherein said binding element comprises an elongated steel element coated with a thermoplastic material, and wherein the coated thermoplastic material has a uniform thickness on each straight portion of the elongated steel element. The building wall structure comprising an inner wall, an outer wall spaced from said inner wall and provided with at least one insulation layer(s) in between, at least one binding element comprising an elongated steel element coated with a thermoplastic material interconnecting said outer wall and inner wall through the insulation layer, wherein ends of said binding element is fixed to the said outer wall and said inner wall respectively and wherein middle portion of said binding element is in contact with the said insulation layer(s). The binding element may comprise a intermediate metallic coating selected from a group consisting of copper, copper alloy, zinc, zinc alloy, nickel, nickel alloy, tin or tin alloy or combinations thereof.

TECHNICAL FIELD

The present invention relates to use of a binding element for a buildingwall structure, particularly to binding elements having a thermoplasticcoating. The binding element has been developed primarily for use inconstruction industry for wall structures made of concrete, brick, andwood or like composition layers, and will be described hereinafter withreference to this application.

BACKGROUND ART

A metal rod that joins and reinforces parts in a structure is well knownin the art. Insulated concrete walls are held together with plurality ofsuch metal rods and are widely used in the construction industry forbuildings. Galvanized wire was often used as a metal rod for thispurpose. In meantime, energy conservation has become a vital componentin the construction industry and developments were focused on increasingthermal insulation and reducing cold bridges between outer and innerwalls. Hence a split hook was developed which functions as a staticconnection between the outer and inner wall, provides a fixation of theinsulation layer and does not form a cold bridge between outer and innerwall. A typical split hook has two components: a metal wire and aplastic plug. EP 0502302, DE8008619 and DE8606959 are few examplesdescribing the split plug system. The problem often encountered is theinstallation of such split hook which is a cumbersome process involvingmultiple steps such as drilling a hole in the outer wall, hammering theplug in to the hole, installing the metal wire in to the plug, coveringthe metal wire with a shield, hammer the metal wire in to the plug andremoving the shield. Another disadvantage of this system is strength.The location of the drilled holes is rather random, sometimes a lot ofanchoring in bricks will occur and sometimes limited anchoring willoccur when the split hook is going through a hole in the brick.

SUMMARY OF THE INVENTION

It is an object of at least certain embodiments of the present inventionto devise a binding element for a building wall structure of concrete orlike composition which address the drawbacks of the present split hooksin the market.

It is an object of at least certain embodiments of the present inventionto devise a binding element that is easier to install in the wallstructure.

It is an object of at least certain embodiments of the present inventionto devise a binding element that is resistant to corrosion and fire.

It is an object of at least certain embodiments of the present inventionto devise a binding element that has a minimal heat conductioncoefficient.

In one aspect, the present invention relates to a use of a bindingelement for a building wall structure, wherein said binding elementcomprises an elongated steel element coated with a thermoplasticmaterial, and wherein the coated thermoplastic material has a uniformthickness on each straight portion of the elongated steel element.Herewith, “uniform thickness” means the thickness of the coating issubstantially same all over each straight portion of the elongated steelelement. The tolerance of coating thickness is within 30%, preferablywith 10%, and more preferably with 5%. The thermoplastic materialcoating is preferably a continuous coating, i.e. the thermoplasticmaterial is coated all over the elongated steel element. Moreover, asexplained in the following the binding element may be bent, especiallyat two ends. At the bent portion, the coating thickness may have bigtolerance, such as 70% or 50%. The inner side of the bent portion mayhave thicker coating while the outer side of the bent portion may havethinner coating. The coating may be formed by any available coatingmethod, such as extrusion. One of many advantages of the presentinvention is the ease in installation of such binding elements in thewall structure. The ends of the binding element can be for instancefixed for example in a bent state in the masonry joint of the brickwall. Furthermore the ratio of thickness of thermoplastic coating andthe steel element may be altered to provide better thermal insulation.The thermal conductivity of such binding elements is minimal.

In one aspect, the present invention relates to a building wallstructure of concrete or like composition comprising an inner wall, anouter wall spaced from said inner wall and provided with at least oneinsulation layer(s) in between, at least one binding element comprisingan elongated steel element coated with a thermoplastic materialinterconnecting said outer wall and inner wall through the insulationlayer, wherein ends of said binding element are fixed to the said outerwall and said inner wall respectively and wherein middle portion of saidbinding element is in contact with the said insulation layer(s).

BRIEF DESCRIPTION OF FIGURES IN THE DRAWINGS

FIGS. 1 and 2 shows a lateral view of a wall structure depicting theembodiment according to the invention.

FIGS. 3 to 10 shows different embodiments of the invention relating tothe binding element.

MODE(S) FOR CARRYING OUT THE INVENTION

FIG. 1 depicts a building wall structure of concrete or like compositioncomprising an inner wall (18), an outer wall (12) spaced from said innerwall and provided with an insulation layer (16) in between, at least onebinding element (20) interconnecting said outer wall and inner wallthrough the insulation layer, the said binding element (20) comprises aelongated steel element (24) preferably having a minimum tensilestrength of at least 100 N/mm² coated with a thermoplastic material (22)of a uniform thickness.

In one embodiment of the present invention, the elongated steel element(24) is coated with thermoplastic material (22) of a substantiallyuniform thickness in its entire length and said binding element has twoedges and the thermoplastic material is not coated thereon, as shown inFIG. 1 and FIGS. 3 to 6. This configuration can significantly simplifythe production process and thus reduce the cost of the binding element.A bundle of steel wire can be first continuously coated withthermoplastic material, such as by extrusion. Then the coated steel wirecan be cut into the desirable length and ready to be in use as a bindingelement or can be used after certain deformation.

In one embodiment of the present invention the elongated steel element(24) is coated with thermoplastic material (22) preferably the middleportion and end portion of binding element fixed to the outer wall (12),more preferably the middle portion of the binding element. The middleportion of the binding element is the represented as that length whichequates the spacing between outer wall (12) and inner wall (18). Inother words the thickness of insulation layer(s) (16) and the spacing(14) should represent the middle portion. The binding element may besecured to the insulation layer by using a stopper (26).

FIG. 2 depicts a brick wall structure showing layers of brick whereinthe binding elements are fixed in a bent state in to the masonry jointduring brick wall construction. As an example, the number of bindingelements ranges from 4 to 5/m² of the wall structure. When a totaltensile strength of 3500 N/m² is intended to reach, this means in thecase of 4 binding elements are applied per square meter, 875 N perbinding elements is required. When a steel wire with a diameter of 4 mmis used, resulting in a required tensile strength of the wire of 70N/mm². When a steel wire with a diameter of 3 mm is used, a minimumtensile strength of 125 N/mm² is required. In order to keep the bindingelement made of steel wire in function, in particular for a longer time,the tensile strength of binding element is at least 100 N/mm².

The binding elements have a standard length of 15-20 cm, may have ahigher range from 40-60 cm, such as about 50 cm, and may also have arange from 15-60 cm. Importantly, the binding elements according topresent application having a length ranging from 40-60 cm can beinstalled without severe buckling. According to European regulations, astandard insulation in a building wall structure now is about 18 cm,while the standard insulation thickness is increasing and by 2018 thiswill be about 30 cm. Therefore, the binding element trend is towardsincreasing lengths as the insulation thickness is increasing.

The term “building wall structure” refers to a wall as used in theconstruction industry. Typically, the wall structure may be made fromlayers of bricks; the term may also refer to concrete or wood or likestructures.

In one embodiment of the present invention the tensile strength ofbinding element is at least 100 N/mm², preferably in range of 100-125N/mm². The tensile strength of a test specimen is the breaking load ofthe test specimen per unit of unstrained cross-sectional area. Thetensile strength is expressed in newtons per square millimeter ormegapascals.

In one embodiment of the present invention the binding element is inaccordance with regulations specified in NEN-EN 846.

In one embodiment of the present invention the shape of said elongatedsteel element is selected from the group consisting of I-profile,H-profile, round, flat, square, rectangular, triangular, trapezoidal,oval, half-round and mixtures thereof. In another embodiment of thepresent invention the elongated steel element is an elongated steel wirehaving a diameter ranging from 2 mm to 5 mm.

In one embodiment of the present invention the thermoplastic coating isselected from a group consisting of polyolefins, foamed thermoplasticresins, thermoplastic polyurethane. Examples of suitable thermoplasticmaterials are: polyethylene (PE), polypropylene (PP), polystyrene (PS),polyethylene terephthalate (PET), polyethylene napthalate (PEN),polybuteen terephthalate (PBT) polyvinylchloride (PVC), polyamide (PA),polyester (PES), polyimide (PI), polycarbonate (PC), styreneacrilonitryl (SAN), acrylonitril-butadiene-styrene (ABS), thermoplasticpolyurethane (TPU), thermoplastic polyolefins (TPO), thermoplasticcopolyetheresters, copolymers of these polymers or similar materials.

In one embodiment of the present invention the elongated steel elementis covered with an intermediate metallic coating. The intermediatemetallic coating is a copper, copper alloy, zinc, zinc alloy, nickel,nickel alloy, tin or tin alloy or combinations thereof. Anotherpreferred method is to coat the elongated steel element by running itthrough a bath of molten metal. This method is particularly suited tocoat the elongated steel element with zinc (hot dip galvanising) or azinc alloy—such as zinc aluminium alloy like Bezinal® coated wire ofBekaert—or copper or a copper alloy or tin. FIGS. 3 to 6 depict certainembodiments of the present invention showing the intermediate metalliccoating (23).

In a further embodiment the elongated steel element is a steel wire anddiameter of said steel wire is at least 0.2 mm and the thickness ofintermediate metallic coating is at least 20% of the steel wirethickness. In one embodiment the total diameter of the steel wire withthe coating is lower than 5 mm. In a preferred embodiment the totaldiameter of the steel wire with the coating is lower than 3 mm, and mayvary between 0.60 mm and 1.60 mm.

In yet a further embodiment the steel wire is a low carbon steel wirewith carbon content below 0.20 wt %. In this embodiment the steel wirehas preferably a carbon content ranging between 0.04 wt % and 0.20 wt %.The complete composition of the wire rod may be as follows: a carboncontent of 0.06 wt %, a silicon content of 0.166 wt %, a chromiumcontent of 0.042 wt %, a copper content of 0.173 wt %, a manganesecontent of 0.382 wt %, a molybdenum content of 0.013 wt %, a nitrogencontent of 0.006 wt %, a nickel content of 0.077 wt %, a phosphoruscontent of 0.007 wt %, a sulfur content of 0.013 wt %.

In a further embodiment the elongated steel element is a stainless steelalloy wire and diameter of said stainless steel alloy wire is at least0.2 mm and the thickness of intermediate metallic coating is at least20% of the steel wire thickness. The stainless steel alloy is selectedfrom a group consisting of 201, 202, 301, 302, 303, 303Se, 304; 304L,309S, 310S, 306, 316L, 317, 317L, 321, 329, 330, 347, 409, 410, 416,416Se, 420, 430, 440C, 442, 904L, 17-4 PH, 17-7PH, 2205, CA-6NM, CA-15,CA-40, CF-3, CF-3M, CF-8, CF-8M, CH-20, CK-20, HF, HH, HK.

In another embodiment the steel wire is a high carbon steel wire with acarbon content above 0.25 wt % and lower than 1.0 wt %. The steel wireis highly mechanically deformed.

In one embodiment of the present invention an adhesion layer is at leastpartially applied between the elongated steel element and thethermoplastic coating, the adhesion layer comprises a compound selectedfrom organo functional silanes, organo functional titanates, and organofunctional zirconates.

The adhesion layer is selected from organo functional silanes, organofunctional titanates and organo functional zirconates which are known inthe art for said purpose. Preferably, but not exclusively, the organofunctional silanes are selected from the compounds of the followingformula:

Y—(CH₂)n-SiX3

wherein: Y represents an organo functional group selected from —NH2,CH₂═CH—, CH₂═C(CH₃)COO—, 2,3-epoxypropoxy, HS— and, Cl—X represents a silicon functional group selected from —OR, —OC(═O)R′,—Cl wherein R and R′ are independently selected from C1 to C4 alkyl,preferably —CH₃, and —C₂H₅; and n is an integer between 0 and 10,preferably from 0 to 10 and most preferably from 0 to 3.

The organo functional silanes described above are commercially availableproducts.

The thickness of thermoplastic material ranges from 150 μm to 1000 μm,preferably from 250 μm to 500 μm.

In one embodiment of the present invention the thermoplastic materialmay further comprise coloring agents. The advantage of such coloringagent is to impart color to the portion of binding element which isstill exposed during construction of wall and such color may also haveglow in the dark agents which can be used for safety purposes so thatthese protruding binding elements are visible in the dark. Some examplesof such coloring agents are color masterbatches which impart color toplastics.

In one embodiment of the present invention the thermoplastic materialmay further comprise flame retarding agents. Some examples of such flameretarding are bishydroxydeoxybenzoin, bromine or non-halogenated agentsthat are added to thermoplastic.

The term “thermal conductivity” is defined as the quantity of heattransmitted through a unit thickness in a direction normal to a surfaceof unit area, due to a unit temperature gradient under steady stateconditions. Thermal conductivity λ is expressed in W/Km. Some values:steel has a HTC of 50 W/Km; stainless steel of 15 W/Km. In oneembodiment of the present invention the binding element has thermalconductivity below 5 W/Km, preferably below 2 W/Km, more preferablybelow 1 W/Km.

In one embodiment of the present invention at least a portion or theends of the binding element has a surface texture selected from a groupconsisting of taper, indentation, serration, thread, ribbed andcombinations thereof. Such a surface provides better anchorage to thewall structure. For instance an indentation in the ends of the bindingelement improves anchorage to the cement mortar embedded in the masonryjoint during brick wall construction. Such surface texture may beimparted on the elongated steel element by passing through surfacetextured rollers.

In one embodiment of the present invention at least a portion or theends of said binding element are bent at angle ranging from 20° to 90°with respect to the axis of the middle portion of the said bindingelement. FIGS. 3 and 4 illustrate a structure with “L-shape” at two endsides.

In one embodiment of the present invention at least a portion or theends of said binding element are crimped. FIGS. 5 and 6 show such acrimped or wavy structure. The advantage of this form is to providebetter anchorage of the binding agents to the wall structure.

In another embodiment of present invention, a portion or one end of saidbinding element is bent at angle ranging from 20° to 90° with respect tothe axis of the middle portion of the said binding element and the otherportion or end is crimped or waved. As an example, such a structure isshown in FIG. 7.

In still another embodiment of present invention, a portion or one endof said binding element has a surface texture selected from a groupconsisting of taper, indentation, serration, thread, ribbed andcombinations thereof and the other portion or end is crimped or waved.As an example, such a structure is shown in FIG. 8.

In still another embodiment of present invention, at least one crimpedor waved portion is introduced in-between the two ends of said bindingelement. As an example, such a structure is shown in FIG. 9.

In yet another embodiment of present invention, at least a portion orthe ends of said binding element are firstly bent at angle ranging from20° to 90° with respect to the axis of the middle portion of the saidbinding element, and then the bent portion is further bent at angleranging from 20° to 90° with respect to the axis of the bent portion. Asan example, FIG. 10 shows such a bent structure at one end of saidbinding element.

1-15. (canceled)
 16. Use of a binding element for a building wallstructure of concrete or like composition, wherein said binding elementcomprises an elongated steel element coated with a thermoplasticmaterial, and wherein the coated thermoplastic material has a uniformthickness on each straight portion of the elongated steel element. 17.Use of the binding element of claim 16, wherein shape of said elongatedsteel element is selected from the group consisting of I-profile,H-profile, round, flat, square, rectangular, triangular, trapezoidal,oval, half-round and mixtures thereof.
 18. Use of the binding elementaccording to claim 16, wherein said elongated steel element is anelongated steel wire having a diameter ranging from 2 mm to 5 mm. 19.Use of the binding element according to claim 16, wherein said elongatedsteel element has a minimum tensile strength of at 100 N/mm² and alength ranging from 40 cm to 60 cm.
 20. Use of the binding elementaccording to claim 16, wherein said thermoplastic material is selectedfrom a group consisting of polyolefins, foamed thermoplastic resins,thermoplastic polyurethane.
 21. Use of the binding element accordingclaim 16, wherein an adhesion layer is at least partially appliedbetween the elongated steel element and the thermoplastic coating, theadhesion layer comprises a compound selected from organo functionalsilanes, organo functional titanates, and organo functional zirconates.22. Use of the binding element according to claim 16, comprising athermoplastic coating in its entire length of said elongated steelelement, and wherein said binding element has two edges and thethermoplastic material is not coated thereon.
 23. Use of the bindingelement according to claim 16, said thermoplastic coating comprises acoloring agent and/or a flame retardant agent.
 24. Use of the bindingelement according to claim 16, wherein thickness of said thermoplasticcoatings ranges from 150 μm to 1000 μm.
 25. Use of the binding elementaccording to claim 17, wherein said elongated steel element is coveredwith an intermediate metallic coating and wherein said intermediatemetallic coating is selected from a group consisting of copper, copperalloy, zinc, zinc alloy, nickel, nickel alloy, tin or tin alloy orcombinations thereof.
 26. Use of the binding element according to claim16, wherein at least a portion or the ends of said binding element has asurface texture selected from a group consisting of taper, indentation,serration, thread, ribbed and combinations thereof.
 27. Use of thebinding element according to claim 16, wherein at least a portion or theends of said binding element are bent at angle ranging from 20° to 90°with respect to the axis of the middle portion of the said bindingelement.
 28. Use of the binding element according to claim 16, whereinat least a portion or the ends of said binding element are crimped orwaved.
 29. A building wall structure comprising an inner wall, an outerwall spaced from said inner wall and provided with at least oneinsulation layer(s) in between, at least one binding element as definedin claim 16 interconnecting said outer wall and inner wall through theinsulation layer, wherein ends of said binding element are fixed to thesaid outer wall and said inner wall respectively and wherein middleportion of said binding element is in contact with the said insulationlayer(s).
 30. The building wall structure of claim 29, wherein thelength of the said middle portion of said binding element equates thespacing between the said outer wall and inner wall.